1. Field of the Invention
The invention is directed to a process and apparatus for the smelting reduction of ores or pre-reduced metal carriers which arrive in a separate settling tank from a smelting reduction reactor through a connection conduit in the form of an emulsion composed of slag, liquid metal and floating coke particles and are converted in the settling tank to form pig iron with a low carbon content by blowing oxygen.
2. Discussion of the Prior Art
A process for the production of iron in which a smelting vessel is coupled with an ore reduction vessel and the reaction gases emerging from the iron melt are partially after-burned in the smelting vessel is known from EP 0 126 391 A1. For this purpose, oxygen top-blowing nozzles whose blowing direction is directed approximately to the center of the bath are arranged in an upper gas space of the smelting vessel. An afterburning is achieved by having gas jets, which act as free jets along a section of adequate length in the gas space of the smelting vessel, suck in an amount of the reaction gases from the gas space. This amount is a multiple of the volume of the oxygen introduced by the nozzles. The ore reduction vessel is connected with the smelting vessel via a discharge device and a fall line. In addition, a smelting reduction vessel, which is connected via a connection piece with a smelting furnace so that the molten substance can flow from one vessel to the other, is known from JP 62228420 (Application No. 86-70897). Oxygen top-blowing lances project into the upper pan of the smelting furnace. In the known processes and devices described above, the molten substance flows to a settling tank as an emulsion of metal, slag and coke particles.
The known processes and devices described above have the disadvantage that floating coke separated in the settling tank remains in this tank. Typically, the coke particles float near or at the surface of the emulsion in the settling tank. Consequently, this coke must be oxidized along with the other contents to achieve the aimed for reduced carbon content in the metal. As a result, the surplus coke is lost in the known processes and the corresponding oxidation heat must be negated by cooling to prevent excess temperatures. Moreover, the installed top-blowing oxygen lances do not permit thermal energy to be supplied independently to the process as would be necessary in the event of disturbances in the process to prevent congealing of a hearth of the settling tank.